"on flat surface" is correct and usable in written English.
Example sentence: "Place the plate on a flat surface to prevent it from spilling food."
For instance, CTT gives the same one point to each of mountain climbing and walking on flat surface.
(See below) Line 2: Lay page on FLAT surface.
Some parts of the aqueous suspension were used to deposit the nanoparticles on flat surface of c-Si wafer.
Firstly, a time series of data for the solar radiation on flat surface in Germany was developed.
The design consists of physiological ankle movements during walking on flat surface as well as uneven terrain.
Surface grinding is a familiar method used in the division of manufacturing in order to generate smooth finish on flat surface.
DLC films were subjected to friction and wear tests using a ball-on-flat surface friction apparatus in solutions of 3 mass% NaCl, 0.05 N HCl, 0.05 N H2SO4 and 0.05 N HNO3.
Baseball, basketball and football are played on flat surfaces designed to give true bounces.
It can balance an iPhone at different angles on flat surfaces.
It only works on flat surfaces, since it functions like a suction cup.
While skating on flat surfaces, the player may manual in multiple ways via button combinations.
